4 speed help please

db · Post by db » Sun May 26, 13 10:09 am

I'm confused. What the hell is the point of the front bearing retainer?

What does it do apart from guide any leaking fluid into the clutch?

Is has that long extension tube over the input shaft for what reason? Why don't they put another bearing near the end to support the shaft better?
The front bearing being a round ball type cannot prevent some rocking motion in the shaft so why does no-one make a twin ball or cylindrical type roller bearing conversion?

I'm wondering if it's possible to have a new retainer made which will hold a bigger or even 2x oil seals and maybe a bronze bush near the pointy end.

Or, is there something amiss inside the gearbox which should be preventing this movement in the shaft in the first place?

db · Post by db » Sun May 26, 13 10:13 pm

With the front housing off, the input shaft can be rocked by 0.5 degree or 0.1" at the pointy end.
Is something worn (bearings are all new) or is this normal???

Mick70RR · Post by **Mick70RR** » Sun May 26, 13 10:49 pm

It's normal Paul. The input shaft is held in the crank bushing so it can't move when it's installed.

VGVIP · Post by **VGVIP** » Mon May 27, 13 12:31 pm

The tube part also guides the throw out bearing if it is anything like the limited number of manual gearboxes I have worked on.

Agree about the movement.... you must have the bush in the end of the crank.
Not sure about mopar but some manufacturers leave the bush out on auto cars only inserting it on manual cars.
so if your is a conversion you will need to make sure you have inserted (the correct) bush

Adrian Worman · Post by **Adrian Worman** » Mon May 27, 13 1:32 pm

I always use the roller bearing that was used in the late Dakota/Ram 360 and 318's, it fits all cranks without machining and supports the input shaft better and closer to the centre plate.

Cannonball · Post by **Cannonball** » Mon May 27, 13 3:56 pm

something odd must be going on my 70 runner had a bollaxed crank bush and the trans never leaked

Philth · Post by **Philth** » Mon May 27, 13 7:41 pm

Input shaft retainer supports the clutch throw-out bearing (acts as a slider).

It is gasketed to the box and also incorporates a shaft seal.

The crankshaft will also have a bearing in either sintered bronze or roller bearings and supports & guides the input shaft end nose in the crank for correct clutch alignment & support (this feature is only found on RWD manual cars, even to this very day!).

This has already all been said by much cleverer people than me but what the hell, eh! Had to replace the input shaft bearing & clutch on mine many moons ago when it used to he a 4 speed motor....

db · Post by db » Mon May 27, 13 11:40 pm

Thanks for the responses all.
I've had a couple of days to calm down from my original rant

I've had a busy weekend so I've not even thought about it, which is no bad thing, so I'll start with a fresh brain in the next few days.

All part of the steep Mopar learning curve

db · Post by db » Tue May 28, 13 4:09 pm

I've checked the bearing in the crank- absolutely fine.
The only thing I can come up with is that the new oil seal from the kit is crap.
Gonna look up a better quality one.

latil · Post by **latil** » Tue May 28, 13 5:04 pm

What's the shaft like where the seal runs? Has the old seal worn the shaft a few thou in that area?

Mick70RR · Post by **Mick70RR** » Tue May 28, 13 10:20 pm

You may have damaged the seal when you slid the bearing retainer over the splines. Make sure the splines don't have any rough edges and try winding a layer of ptfe tape over the splines before you slide the retainer on.

db · Post by db » Tue May 28, 13 10:31 pm

Funnily enough Steve I've just checked a bike part I'm selling. I thought the seal had just polished it but it was worn from 40mm to 39.96.
I'll carefully check my shaft for grooves

Good point Mick, I'll be super-careful with my new seal, ordered today

Philth · Post by **Philth** » Wed May 29, 13 3:06 pm

Can't quite remember but does the manual 'box have a breather? If not/or blocked could the oil be pushed past the (weak) seal by the air in the box heating up and expanding?

Just a thought...

db · Post by db » Thu May 30, 13 9:45 am

Thanks mate.
It does and no I haven't checked it yet

db · Post by db » Sun Jun 02, 13 9:28 am

Breather is fine.
NO groove worn in the shaft where the seal lip sits.
NEW seal arrived from Bearing Man and doesn't fit

The old seal is 175 - 125 - 25
The new seal is 175 - 118 - 25 (closest they could find)
Now I expected the inner to be tight but the outer is the puzzle- they're both marked 175 but the new is 0.020" bigger

Anyone in the U.K. supply top quality Imperial seals?